Propeller



Nov. 7, 1933. c. H. HAvlLl. 1,934,668

PROPELLER Filed Aug. 25, 1931 3 Sheets-Sheet l Slmcnto C. H. HAVILL Nov. 7, 1933.

PROPELLER Filed. Aug. 25, 1931 3 Sheets-Sheet 2 3 Sheets-Sheetl 3 A 'gn/ventola M., 544W Nov. 7, 1933. c. H. HAVILL PROPELLER Filed Aug. 25, 119:51

ma@ Q \\\\\N wws Patented Nov. 7, 1933 UNITED STATES PATENT" OFFICE PROPELLER Application August 25, 1931. Serial No. 559,295

Claims.

This invention relates to propellers, and more particularly to propellers in which the pitch of the blades may be varied duringoperation.

It is one of the objects of the present inven- 5 tion to provide a propeller embodying novel means for automatically varying the pitch of the blades during operation.

Another object of the present invention is to provide a variablevpitch propeller wherein the pitch of the blades is limited in a novel manner.

Another object is to provide in a variable pitch propeller a novel construction wherein the pitch of the blades is automatically limited during operation in accordance with variable operating conditions in order to yield maximum propeller efficiency at all times.

A further object is to provide a propeller of the above character embodying a novel arrangement whereby the adjustment of the pitch limiting mechanism is automatically varied upon each movement of the pitch changing apparatus in a predetermined direction, thus eliminating any necessity for skillful manipulation on the part of the operator.

A still further object is to provide in a variable pitch propeller a novel arrangement of parts which are light in weight, compact in form, and unusually'efcient and reliable in operation and which are entirely enclosed within the propeller hub structure so as to offer no appreciable resistance to the air stream passing over the propeller.

Further objects and advantages will appear from the following detailed description when taken in connection with the accompanying drawings, it being expressly understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawings, wherein like reference characters refer to like parts throughout the several views: p

Fig. 1 is an axial view partly in section and partly in elevation of a propeller embodying the present invention;

Fig. 2 is a side view of the propeller shown in Fig. 1 with parts shown in section;

Fig. 3 is a section on line 3-3 of Fig.- 2 with parts shown in elevation;

Fig. 4 is a perspective view of certain of the parts shown in Figs. 1 and 3; and,

Fig. 5 is a perspective view of certain of the parts shown in Figs. 1 and 2.

Referring more particularly to Figs. 1 and 3,

(Cl. 17o- 162) a propeller embodying the principles of the present invention is shown therein as being constituted by an engine shaft 6, or extension thereof, and a hub 'l having a plurality of sockets 8 adapted to rotatably receive the inner or root 60 ends of propeller blades 9, the hub being drivably connected to the shaft and movable longitudinally with respect thereto in response to the thrust of the blades, suitable means being provided to rotate the blades in the sockets to van the pitch thereof during such longitudinal movement, as will appear more-fully hereinafter.

In order to drivably connect the hub '7 with the shaft 6, a driving member or block 10 is splined to the latter and is maintained in fixed T0 relation therewith as by means of split cones 11 and 12 and a nut 13 threadedly connected to the driving shaft 6 and locked to a forward extension of the driving-block 10 by any suitable means, as by a pin 14. The driving block 10 is received in a central opening in the hub and a plurality of rows of suitable bearings 15 are interposed between the. hub and the driving block in order to permit substantially frictionless longitudinal movement between these last 3@ named parts,

Means are provided for rotatably mounting the inner or root ends of the blades 9 in the sockets 8, and preferably such means are so constituted as to be adapted for use with the type of propeller blade now commonly employed. As shown, such means includes 'a split sleeve 16, the inner surface of which conforms substantially to the conguration of the root ends of the blade, the two portions of the sleeve being secured together by an inner ring 17 and an outer ring 18. Each sleeve is so formed on its exterior surface as to provide an annular shoulder 19 forming an inner race for a series of thrust bearings 20, the outer race forsaid bearings being formed by a thrust ring 21 threadedly received .in the outer ends of each of the hub sockets and serving to maintain the propeller blades securely within the sockets. A plurality of ball bearings 22 are positioned at the inner end of each socket between the hub and the ring 17 to decrease the resistance to rotation of 'each blade in its respective socket. Each of the rings 17 is preferably provided with counterweights or enlargements on diametrically opposite sides, as indicated at 23, Fig. 4, in order to substantially neutralize the net elect of torsion on the propeller blades.

Means are provided for effecting rotation of the blades in their sockets during longitudinal 110 movement of the hub on the shaft in response to the thrust of blades during operation in order to vary the pitch thereof. As shown, such means are constituted by a link 24, Fig. 3, one end of which is pivotally secured to a stud 25 threadedly received by the ring 17 on the root end of the blade, and the other end of which is pivotally fastened to a plate or arm 26 formed integrally with the driving block 10 or otherwise rigidly securedA thereto. From the above construction it will be apparent that during forward thrust-responsive movement of the hub relative to the shaft, each blade will be rrotated in its socket to vary the pitch thereof, it being pointed out that the pitch of the blades is decreased during forward movement of the hub relative to the shaft.

As shown, means are provided for yieldingly opposing forward movement of the hub with respect to the shaft and preferably such means are constituted by a plurality of resilient members, such as for example, coil springs 27, interposed between the hub and a plate 28 secured in any suitable manner to the forwardly extending portion of the driving block 10.

In order to limit the forward, pitch-changing movement of the hub, adjustable stop means are provided, the adjustment of such means being automatically effected by longitudinal movement of the hub with respect to the shaft. As shown, Fig. 5, such means is constituted by a member 29 rotatably mounted on a stub shaft 30 integral with or otherwise suitably secured to the plate 28, the member 29 being provided with pairs of lugs 31, 32 and 33 of varying length, adapted to selectively engage projections 34, Fig. 1, on the hub to limit forward movement of the latter with respect to the shaft. In order to rotate the member 29 to present different lugs 31, 32, or 33 to act as variable stops for the hub, a ratchet 35 is provided on the member 29 and a cooperating arm 36 is pivotally mounted on the hub for longitudinal movement therewith, a spring 36a being preferably provided for holding the arm 36 in contact with the ratchet 35. The outer end portion of the arm 36 is formed with a projection 37 adapted to engage the teeth of the ratchet 35 so that as the hub moves rearwardly of the shaft in response to the force of springs 27 during a decrease in the effective thrust of the propeller, the arm 36 will cause the' ratchet 35 and member 29 to rotate, thus bringing a different lug 31, 32 or 33 into alignment with the projection 34 on the hub, a spring detent, not shown, or other suitable means, such as the friction existing between the stub shafts 30 and the ratchets, being provided to insure that rotation of the member 29 will be arrested in such a position that one of the lugs 31, 32, or 33 is in axial alignment with the projection 34. I

In the operation of an aeroplane equipped with the present invention, the member 29 is rotated until the short lug 31 is opposite the projection 34 before take-off and the-plane is then taken off in the usual manner, it being pointed out that the short lug 31 allows the hub to move forwardly the maximum distance, thus reducing the pitch `of the blades to a minimum and permitting the propeller to generate a maximum thrust, desirable during take-off. After the plane is in flight, the engine throttle may be closed, thus reducing the thrust of the blades and permitting the hub to move rearwardly on the shaft in response to the expansion of the springs 27, during which movement the member 29 will be rotated by the arm 36, as described above, to bring thelug 32 into alignment with the projection 34. Upon again opening the engine throttle, the hub will move forwardly on the shaft until the projection 34 engages lug 32, in which position of the hub the pitch of the blades will be limited at the most desirable degree for top speed flight. A repetition of the above described operation will cause the member 29 to be further rotated until the long lug 33 is in alignment with the projection 34, this lug limiting thrust-responsive movement of the hub and hence the pitch of the blades at a position which produces the most desirable pitch for cruising.

There is thus provided by the present invention a novel, automatic, variable pitch propeller in which the pitch of the blades is automatically and positively limited at the most desirable and effective angle for various operating conditions encountered during flight. rotatable stop mechanism for arresting forward movement of the hub, and consequent variation in the pitch of the blades, at predetermined positions dependent upon variable conditions of the effective thrust of the propeller, enables maximum propeller eciency to be obtained during all conditions of flight without the necessity of skillful manipulation on the part of the operator. The apparatus is moreover light in weight, sturdy of construction, and positive in operation, which features render the device especially adaptable for use on aircraft.

Although one embodiment of the invention has been disclosed herein, it is to be expressly understood that the same is' not limited thereto but may be embodied in various forms. For example, while the invention has been shown and described in connection with a propeller wherein the pitch of the blades is varied in accordance with variations in thrust, it is equally adapted for use with a propeller the pitch of the blades of which is varied in accordance with other dynamic forces present during operation or by manual control of the operator. Reference will, therefore, be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A variable pitch propeller comprising a rotatable shaft, a hub mounted on said shaft, a. plurality of blades rotatably mounted in said hub, said hub being drivably connected to said shaft and longitudinally movable thereon in response to the thrust of the blades, connections between said shaft and said blades for changing the angularty of the blades in response to movement of the hub, a plate member rigidly mounted on said shaft forwardly of the hub, resilient means interposed between the hub and plate to yieldingly resist forward movementv of the hub on the shaft, and stop means carried by said plate for limiting such forward movement of the hub, said stop means including rotatable members having projections of varying lengths adapted for selective engagement with said hub, and connections between said hub and said rotatable members for turning said rotatable members through a predetermined arc upon each rearward movement of the hub.

2. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to and longitudinally movable on said shaft, a plurality of blades rotatably mounted in said hub, connections between said shaft and said blades for changing the angularity of the blades in response The provision of the shaft, and stop means adjustable during vopera- -tion of the propeller for limiting forward movement of the hub `on the shaft.

3. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to and movable axially of said shaft, a plurality of blades rotatably mounted in said hub, means responsive to axial movement of said hub for varying the pitch of said blades, and means adjustable in response to axial movement of said hub for limiting the axial movement of the hub.

4. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to and movable axially of said shaft, a plurality of blades rotatably carried by said hub, means responsive to axial movement of said hub for varying the pitch of the blades, and means adjustable in response to axial movement of the hub in one direction for limiting axial movement of the hub in the opposite direction.

5. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to said shaft, a plurality of blades rotatably carried by said hub, said hub being movable axially of said shaft in response to the thrust of the blades, means responsive to axial movement of said hub for changing the pitch of the blades, adjustable stop means for limiting movement of the hub in one direction and connections between said hub and said stop means for changing the adjustment of the stop means in response to axial movement of the hub. v

6. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to said shaft, a plurality of blades rotatably carried by said hub, said hub being movable axially of said shaft in response to the thrust of the blades, means responsive to axial movement of said hub for changing the pitch of the blades, and rotatable stop members carried by said shaft for arresting movement of the hub in one direction, said members being rotated by axial movement of the hub in another direction.

7. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to said shaft, a plurality of blades rotatably carried by said hub, said hub being movable axially of said shaft in response to the thrust of the blades, means responsive to axial movement of the hub for changing the pitch of the blades, resilient means yieldingly opposing the thrust-responsive movement of the hub, and stop means adjustable in response to movement of the hub for limiting the thrust-responsive movement of the latter.

8. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to said shaft, a plurality of blades rotatably carried by said hub, said hub being movable axially of said shaft in response to the thrust of the blades, means responsive to axial movement of the hub for changing the pitchof the blades, resilient means yieldingly opposing the thrust-responsive movement of the hub, stop means for positively limiting thrust-responsive movement of the hub, and connections between said hub and said stop means for adjusting said stop means upon movement of the hub in response to said resilient means.

`9. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected thereto, a plurality of blades rotatably carried by said hub, pitch changing mechanism including said hub operatively associated with said blades, and

adjustable stop means for limiting the operative movement of said pitch changing mechanism, said stop means operable by movement of said mechanism including said hub.

10. A variable pitch propeller comprising a rotatable shaft, a plurality of blades drivably connected to said shaft and adapted for rotation about their longitudinal axes, means associated with said blades and including a hub movable in response to the thrust of the blades for varying the pitch of the latter, and means adjustable in response to movement of the pitch changing means in one direction for limiting the pitch of the blades during movement of the pitch changing means in the other direction.

11. In a variable pitch propeller having a hub and a plurality of blades rotatable about their longitudinal axes for changing the pitch thereof, means including said hub for effecting pitch changing rotation of said blades, stop means for limiting operation of said pitch changing means during a decrease in the pitch of the blades, and

means operable upon movement of the pitch changing means during an increase in the pitch of the blades for adjusting said stop means.

12. In a variable pitch propeller having a rotatable shaft, a hub movable longitudinally of said shaft, a plurality of blades rotatably mounted in said hub, means responsive to longitudinal movement of the hub for changing the pitch of the blades, means carried by said shaft for limiting movement of the hub comprising a rotatable member having projections of diierent lengths adapted for selective engagement with said hub, and means connecting said hub and said rotatable member for rotating said member in response to movement of the hub.

13. In a variable pitch propeller for aircraft having a shaft and a hub drivably connected thereto, a plurality of blades rotatably mounted in said hub, a member spaced from said hub along said shaft and drivably connected with the latter, said member and hub being relatively movable along said shaft with respect to each other in response to an operating condition of the propeller, resilient means for yieldingly opposing such relative movement between said member and hub, means for rotating said blades in said hub tovary the pitch during such relative movement, adjustable stop means for limiting the variation in pitch of the blades, and means operated during operation of said pitch varying means for changing the adjustment of said stop means. I

14. A propeller hub comprising a driving mem'- ber, a hub member rotatable with said driving member and longitudinally movable with respect thereto, said hub member being provided with a plurality of radially extending sockets, a sleeve rotatably mounted in each socket, said sleeves being adapted to receive a propeller blade, and a plurality of rotatable stop mechanisms carried by said driving member and cooperating with said hub member for variably limiting longitudinal movement of said last-named member with respect to the driving member.

l5. A propeller hub comprising a driving member, a hub member rotatable with said driving member and longitudinally movable with respect thereto, said hub member being provided with a plurality of radially extending sockets, a sleeve rotatably mounted in each socket, said sleeves being adapted to receive a propeller blade, and a plurality of rotatable stop mechanisms having stop members of variable length and adapted to be rotated by longituidnal movement of the hub member in one direction for positively limiting longitudinal movement of the hub member in another direction.

16. A propeller hub comprising a driving member,` a hub member rotatable with said driving member and longitudinally movable with respect thereto, said hub member being provided with a plurality of radiallly extending sockets, a sleeve rotatably mounted in each socket, said sleeves being adapted to receive a propeller blade, and a plurality of rotatable stop mechanisms carried by said driving member and positioned on diametrically opposite sides thereof, said stop mechanisms having a plurality of stop members of variable length adapted to cooperate with said hub member for variably limiting longitudinal movement thereof with respect to the driving member, and means carried by said hub member for rotating said stop mechanisms during longitudinal movement of the hub member in one direction.

17. In a propeller having a plurality of blades, means actuated by the thrust of said blades for automatically varying the pitch of the blades, means for predetermining the extent of operation of said pitch varying means Within predetermined limits, and means operated by said pitch varying means for varying one of said limits.

18. A propeller of the class described comprising a rotatable shaft, a plurality of blades, a hub for drivably connecting said shaft and blades, means responsive to the thrust of said blades and including said hub for changing the pitch of said blades, and means for variably limiting the extent of operation of said pitch changing means, said limiting means being adjusted by operation of said pitch changing means during an increase in the pitch of the blades.

19.l A Variable pitch propeller comprising a rotatable shaft, a hub drivably connected to said shaft, a plurality of blades rotatably carried by said hub, the latter being movable axially of said shaft in response to the thrust of the blades, means operable during axial movement of the hub for changing the pitch of the blades, resilient means for yieldingly opposing such axial movement of the hub, and stop means adjustable during operation of the propeller for limiting movement of the hub in one direction with respect to the shaft.

20. A variable pitch propeller comprising a rotatable shaft, a hub drivably connected to said shaft, a plurality of blades rotatably carried by said hub, the latter being movable axially of said shaft in response to the thrust of the blades, means operable during such thrust-responsive movement of the hub for decreasing the pitch of the blades, resilient means for normally maintaining the hub in such a position with respect to the shaft that the pitch of the blades will be a predetermined maximum, and stop means adjustable during operation of the propeller for limiting 105 movement of the hub relative to the shaft in the direction to reduce the pitch of the blades.

CLINTON H. HAVILL. Z 

